Gas blast circuit breaker with electromagnetic contact actuating means



TE'II'SUYA FURUKAWA ETAL April 18, 1967 3,315,056

' GAS BLAST CIRCUIT BREAKER WITH ELECTROMAGNETIC CONTACT ACTUATING MEANS Filed Oct. 14, 1964 2 Sheets-Sheet l Apnl 18, 1967 TETSUYA FURUKAWA ETAL 3, 6

GAS BLAST CIRCUIT BREAKER WITH ELECTROMAGNETIC CONTACT ACTUATING MEANS Filed Oct. 14, 1964 2 Sheets-Sheet 2 United States Patent 3,315,056 GAS BLAST CIRCUIT BREAKER WITH ELECTRO- MAGNETIC CONTACT ACTUATING MEANS Tetsuya Furukawa and Yoshio Nitta, Tokyo-to, and N obuaki Kiyokuni, Kawasaki-shi, Japan, assiguors to Fuji Denki Seizo Kabushiki Kaisha, Kawasaki-shi, Japan, a

joint-stock company of Japan Filed Oct. 14, 1964, Ser. No. 403,832 Claims. (Cl. 200-148) The present invention relates to electrical circuit Ibreakers, particularly to a novel high-voltage, gas-blast type circuit breaker.

The interrupting time of a circuit breaker, that is the time period measured from the time of issuing of the tripping command to the time when the current interruption is actually completed, is 3 to 5 cycles on the basis of commercial frequency for ordinary types of circuit breakers widely used today. If this interrupting time could be substantially shortened, the time period necessary to cut out defective parts, when fault occurs in the circuit, from other parts of the circuit would be accordingly shortened, and this would result in an increase in the network stability, whereby the transmission capacity of the transmission line could be increased. This would also result in a decrease in the degree of damage to equipments such as transformers connected in the transmission line and also in facility in repair of these equipments.

It is, therefore, an object of this invention to provide a circuit breaker in Which the interrupting time is substantially shorter than those of the ordinary types, for example, one half of the time hitherto obtainable.

Another object of this invention is to provide a novel method for very quick opening of the contacts utilizing electromagnetic force caused by the discharge current from a capacitor.

A further object of this invention is to provide a novel method of increasing the transmission speed of the tripping command by utilizing an electromagnetic wave, particularly light.

A still further object of this invention is to provide a novel construction wherein the contacts are formed as a part of a valve for a compressed gas, whereby the com pressed gas can be blasted at the same instant as that of the opening of the contacts.

A still further object of this invention is to provide a novel combination of the circuit breaker and a disconnecting switch connected in series, in which the disconnecting switch is caused to operate at a certain time after the operation of the main breaker contacts.

A still further object of this invention is to provide a novel method in which the starting of the discharge of the capacitor is controlled from the ground (earth) side by an electromagnetic wave, and the disconnecting switch is operated by a compressed gas,-thereby to cause the breaker and the disconnecting switch to operate in an interrelated manner and with a certain time delay.

A still further object of the invention is to provide a novel method in which a capacitor placed in a high potential portion can be commanded from the ground (earth) side to charge or to cause tripping.

According to the present invention, there is provided a circuit breaker comprising a first contact, a second contact disposed coaxially with said first contact and adapted to be movable on the common axis to contact with said first. contact, said second contact having the function also of a blow valve of compressed gas, a casing which encloses both said contacts and is normally filled with a compressed gas and electrically insulated from ground potential, a flange member provided on said second contact, a driving coil fixedly disposed to be closely coupled,

3,315,056 Patented Apr. 18, 1967 in an electromagnetic manner, with said flange member, a capacitor connectable to said driving coil through a switching element, and a device to charge said capacitor, said members being combined so that an electrostatic charge in said capacitor is discharged into said driving coil by the operation of said switching element to cause a current to flow through said driving coil, the resulting repulsive force between said current in said driving coil and an induced current in said flange member causes said second contact to separate from said first contact, and at the same time the resulting electric are formed between said contacts is extinguished and interrupted by the compressed gas in said casing blown from around the region surrounding said contacts by said blow valve function of said second contact.

The nature, principle, and details of the invention will be more clearly apparent from the following description with respect to some preferred embodiments, by way of example, with reference to the accompanying drawings, in which the same or equivalent members are designated by the same reference numerals, and in which:

FIG. 1 is a vertical sectional view showing one embodiment of the circuit breaker and the disconnecting switch according to the invention;

FIG. 2 is a sectional view showing a part of the contact of the circuit breaker shown in FIG. 1; and

FIG. 3 is a vertical sectional view of another example of the circuit breaker and the disconnecting switch in combination.

Referring to FIG. 1, an interrupting chamber 1 which is at a high potential is insulated from the ground by two hollow porcelain insulators 2 and 3 and has a breaker casing 4 through one end of which a porcelain bushing 5 is passed. Inside of the bushing 5 there is disposed a hollow conductor 6, one end of which opens to the outside atmosphere and the other end enclosed in the casing 4 is provided With a nozzle-shaped stationary contact 7 and a resilient annular packing 8 being inserted into the end part thereof.

A movable nozzle-shaped contact 11, which contacts with the stationary contact '7, is fitted in a slidable and hermetic manner in the inner end of a guide hole 13 provided in a metal support 12 mounted on the other end of the casing 4, and the other end of the hole 13 opens to the atmosphere. A flange 14 is formed integrally with and concentrically about the movable contact 11.

An annular driving coil 15 is imbedded in an annular insulator 16 secured to the metal support 12. A spring 17 is inserted between the flange 14 and the metal support 12 and simultaneously pushes the end 18 of the movable contact 11 toward the stationary contact 7 and the front face of the flange 14 toward the driving coil 15.

The diameter of the end portion 13 of the movable contact 11 which contacts the stationary contact 7 is larger than other parts as indicated in FIG. 2, and the inner surface of the end portion is formed into a nozzle throat part 19.

The interior of the casing 4 is communicative through the porcelain insulator 2 with a tank 21 at ground potential and filled with a compressed gas such as compressed air, and the casing 4 is also filled with a gas of higher pressure than the outside. As indicated in FIG. 2, when the movable contact 11 is contacting with the stationary contact 7, a force F due to the gas pressure in the casing 4 and given by the following equation is exerted around the movable contact 11 in the direction of the directional arrow A.

where D is the effective diameter of the packing 8, D is the outside diameter of the movable contact 11, and

P is the pressure difference between the inside and the outside of the casing 4. Because of the above mentioned force F and the force due to the spring 17, the movable contact 11 is pushed against the stationary contact 7, thus firstly maintaining good electrical conductance through the contact and secondly blocking the pressure gas from leaking into the hollow space inside the fixed contact 7 and the movable contact 11 and then to the outside atmosphere.

A valve 25 closes the opening port to the atmosphere of the hole 13 in the metal support 12. The compressed gas which drives a piston 26 connected to the valve 25 against the force of the spring 27 is supplied from the casing 4, further therefore, from the tank 21, through a control valve 28 which operates with a certain time delay.

A series-connected disconnecting switch 30 is operated in relation with the open and close operation of the movable contact 11. The disconnecting switch 30 is enclosed in a hollow porcelain insulator 31 attached at approximately right angles to the bushing at is end opposite to the stationary contact 7. A stationary contact 33 of the disconnecting switch 30 is fixed to the inner side of a metal flange 32 closing the free end of the porcelain insulator 31. A movable contact 34 of the disconnect-ing switch 30 has a piston 36 movable within a metal cylinder 35. A spring 37 is provided to act on the lower surface of the piston 36 and push the movable cont-act 34 upwardly so that it contacts the stationary contact 33. The space 38 inside of the porcelain insulator 31 and the space 39 within the cylinder 35 above the piston 36 are connected to the space inside the casing 4 through a passage 40. The space 42 inside the cylinder and below the piston 36, which encompasses the spring 37 in connected to the space 38 or to the hole 43 opening to the atmosphere through a switching valve 41. A control pressure gas, which will be described later, acts through a pipe 45 on a piston 44 connected to the movable part of the valve 41.

The metal cylinder 35 is electrically connected with the hollow conductor 6. Therefore, an electrically conductive path to be connected to the circuit is formed from the metal flange 32, through the stationary contact 33 of the disconnecting switch, the movable contact 34, the cylinder 35, the hollow conductor 6 in the interrupting chamber 1, the stationary contact 7, the moving contact 11, the metal support 12, and to the casing 4.

A voltage dividing capacitor 46 is connected between the flange 32 and the casing 4, in parallel with the disconnecting switch 30. A linear resistor 47 is connected between the stationary contact 7 and the casing 4, in parallel with the breaker contacts, and absorbs the abnormal voltage which may arise between the contacts at their opening, and also serves as a voltage divider.

A control pressure gas is supplied from the tank 21, through a valve unit 51 and an insulated pipe 50, to the control valve 28 and further to the piston 44 attached to the disconnecting switch to impart fluid operational command thereto.

A valve 52 of the valve unit 51 is pushed in the direction to interrupt the passage between the pipe 50 and the tank 21 by the force of compression spring 55 which acts on a piston 54 in a cylinder 53. The cylinder 53 is provided with an opening 59 so that said opening 59 communicates the pipe 50, which is in a state disconnected from the tank 21 by the valve 52, with the outside atmosphere at the indicated position of the piston 54. On the other hand, the cylinder 53 is provided with a valve seat 56 which is moved rightward together with the valve 52 so that communication between the pipe 50 and the opening 59 is broken at the position where the valve 52 has moved rightward, that is, the pipe 50 is communicated with the tank 31. A solenoid valve 57 connects the tank 21 with the space inside the cylinder 53 on the left of the piston 54, and another solenoid valve 58 connects the same space to the outside atmosphere. Energizing coils 57a and 58a for said solenoid valves are connected respectively with the trip command circuit terminal 61 and the closing command circuit terminal 62.

The aforementioned driving coil 15 in the interrupting chamber 1 is connected to a capacitor 72 through a switching element such as a spark gap 71. To charge this capacitor 72, a transformer 74 placed in the high voltage portion of the breaker is connected thereto through a rectifier 73. This transformer 74 is supplied with a power, through a plurality of insulating transformers 75 in cascade connection placed in the porcelain insulator 3, from the terminals 76 of an A.-C. power source on the ground (earth) side. An electromagnetic wave receiver 77, e.g., a photo-electric relay made of a photo-electric material such as cadmiumsulphide, receives flashing light signals from an electromagnetic wave transmitter such as a flash lamp 78 placed on the ground side through a light-guide bar 79 made of a transparent and highly refractive material such as methacrylate resin and imparts electric pulses to the starting electrode 80 of the spark gap 71. The flash lamp 78 is connected to the tripping command circuit terminals 61.

With the apparatus in the illustrated state, the interrupting chamber 1 and the series connected disconnecting switch 30 are both closed. When the trip command is imparted to the terminals 61, the flash light 78 is lit, and its light passes through the light-guide bar 79 and reaches the photo-electric relay 77 where the light signal is converted into an electric impulse. This impulse is imparted to the starting electrode 80, thus causing the spark gap 71 to become conductive, whereby the electrostatic charge accumulated in the capacitor 72 is discharged instantaneously into the driving coil 15. The flange 14 on the movable contact 11, which is electromagnetically closecoupled with the driving coil 15, functions as a secondary short-ring with respect to the driving coil 15, and a large current is induced therein. The resulting large electromagnetic repulsive force acting between the driving coil 15 and the flange 14 causes the movable contact 11 to separate almost instantaneously .from the stationary contact 7. The compressed gas in the casing 4 flows through the opening gap between the stationary contact 7 and the movable contact 11 into the hollow conductor 6 of the stationary contact and also through the interior of the movable contact 11 and the hole 13 of the metal support 12, both paths leading to the outside atmosphere, and blows out the electric arcs developed between the contacts. The movable contact 11 is kept in the open position by the difference between the gas pressures at the entrance and the exit of the nozzle throat portion 19.

The trip command signal applied to the terminal 61 energizes also the energizing coil 57:: of the solenoid valve 57 connected in parallel with the flash lamp 78, thus causing the solenoid valve 57 to open and the cylinder space on the left side of the piston 54 is communicated with the tank 21. Accordingly, the pressure gas in the tank 21 is supplied into the space at the left of the piston '54 arranged in the cylinder 53 to move the piston 54 to the right, thereby interrupting communication between the pipe 50 and the opening hole 59. Simultaneously, the valve 52 is moved to the right and supplies pressure gas from the tank 21 to the pipe '50. The pressure gas which has entered the pipe 50 arrives at the high potential portion within a short time and, through the pipe 45, acts on the piston 44 attached to the disconnecting switch '30 and pushes the piston 44 upward. The valve 41 coupled with the piston 44 interrupts the communication between the space 42 and the space 38 and also at the same time releases the pressure gas in the space 42 through the port 43 to the outside atmosphere. Consequently, the pressure gas acting on the upper side of the piston 36 pushes down the movable contact 34, which is formed integrally with the piston 36, against the compressive force of the spring 37, thereby to open the contacts.

At the same time, the compressed gas in the pipe 50 is sent to the control valve unit 28 through a pipe 280, and at a certain time after the operation of the disconnecting switch 30, in other words, after a certain time delay from the supplying of the compressed gas into the pipe 28a, the control valve 28 opens. Consequently, the pressure gas in the casing 4 passes through the control valve 28 to the piston 26 and drives the piston 26 and the directly coupled valve to the left, thereby closing the port of the hole 13 and thus preventing wasteful outflow of the compressed gas in the casing 4. The closing of the port of the hole 13 causes the pressures inside and outside of the moving contact 11 to balance each other, and the end of the moving contact 11 is pushed against the stationary contact 7 by the spring 17. The control valve 28 returns to the original position after a certain time and stops supplying compressed gas from the casing 4 and also releases to the outside atmosphere the pressure gas acting on the piston 26. Consequently, the piston 26 and, therefore, the valve 25 are returned rightwardly by the force of the spring 27, thereby opening the port of the hole 13.

Between the application of thetripping signal and the complete opening of the disconnecting switch 30, there exists a certain time delay due to the operational time of the solenoid valve 57 and valve 51 and flow time of the compressed gas from the tank 21 to the high potential side, and in ordinary design, this delay is of a number of cycles in terms of commercial frequency. Because of the existence of the control valve 28, the closing of the port of the hole 13 and hence the closing of the path of the movable contact 11 are further delayed by a predetermined time from the opening of the disconnecting switch 30, whereby the opening of the disconnecting switch before the closing of the movable contact 11 is assured. As mentioned before, the movable contact 11 is opened almost at the same instant as the application of the tripping command signal, interrupting the current at the first zero point of the current and amply restoring insulation between the two contacts. Consequently, by causing through the application of a tripping signal through a pressure gas, the contact of the disconnecting switch and the valve for closing the port of the main breaker to operate successively with predetermined time lag as described above, amply satisfactory performance of the apparatus as a circuit breaker can be obtained.

When the breaker is to be closed, the closing signal is applied to the terminal 62, whereupon the closing solenoid valve 58 opens, thus allowing the compressed gas at the left side of the piston 54 in the cylinder 53 to discharge to the outside atmosphere, whereby the piston 54 is driven to the left by the gas pressure and by the force of the spring 53, thus causing reclosing of the valve 51 and discharge of the compressed gas filled in the pipe 50 to the outside atmosphere. Consequently loss of the pressure in the pipe 50 causes the valve 41 attached to the disconnecting switch 30 to return to the original position, and this in turn allows the movable contact 34 of the disconnecting switch to be closed by the force of the spring 37.

Another example of this invention is indicated in FIG. 3, where the driving signal to the piston 44 of the disconnecting switch 30 is applied in relation with the pressure gas blast from the hole 13 of the metal support 12 to the outside atmosphere after the opening of the main contact 11.

In the drawing, the valve 25 for closing the port of the hole 13 is formed so as to have a hollow space, and a piston 102 pressed by a spring 101 is guided in said hollow space. The valve 25 is formed in one piece integrally with a piston-shaped flange 104 which is guided within a cylinder 103. The pressure gas from the casing 4 acts on the flange 104 through the valve 28. The piston 102 is provided with a piston valve 105 which controls the supply of the pressure gas from the casing 4 to the pipe 50. On the ground side a valve 110 for discharging the pressure gas in the pipe 50 to the outside atmosphere is provided and operated pneumatically by the closing solenoid valve 58.

The capacitor which supplies energy to the driving coil 15 consists of two capacitors 72a and 72b as shown, which are adapted to be connected in turn into the discharge circuit to the driving coil 15 by a change-over switch 111 which is operated in relation to the pressure gas blast from the hole 13 of the metal support 12 at the time of opening of the movable contact 11 of the interrupting chamber 1. Therefore, this arrangement is especially advantageous for high-speed reclosing of the interrupting chamber 1.

In the above example of this invention, the valve body 25 is pushed to the right by the pressure gas blast through the hole 13, at the time of opening of the movable contact 11 by the tripping signal. This also pushes the piston valve coupled with the valve 25 to the right and communicates the casing 4 with the pipe 50, whereby, as described in connection with FIG. 1, the disconnecting switch 30 and, after a certain time delay, the control valve 28 are operated. The compressed gas through the control valve 28, which is now operated, reaches the flange 104, thus pushing the flange 104 to the left, whereby the valve 25 closes the hole 13, and at the same time drives the piston 102 and piston valve 105 to the left, thus shutting the passage between the casing 4 and the pipe 50.

What we claim is:

1. A gas blast circuit breaker with electromagnetic contact actuating means comprising a first contact, a second contact of construction normally in contact with said first contact and having a coaxial passage therethrough disposed coaxially with said first contact and adapted to be movable on the common axis to contact said first contact, a casing which encloses both said contacts and is normally filled with a compressed gas and electrically insulated from ground potential, means to prevent leakage of the compressed gas in said casing between the contacting surfaces of the first and second contacts when in contact, a flange member provided on said second contact, a driving coil which is fixedly disposed so as to be closely coupled, in an electromagnetic manner, with said flange member, a switching element, a capacitor connectable to said driving coil through said switching element, and means to charge said capacitor, said switching element, capacitor and driving coil being combined so that an electrostatic charge in said capacitor is discharged into said driving coil upon operation of said switching element to cause a current to flow through said driving coil, whereby said second contact will be separated from said first contact by the resulting repulsive force between said current in said driving coil and an induced current in said flange member.

2. A gas blast circuit breaker with electromagnetic contact actuating means having a passage therethrough comprising a first contact, a nozzle shaped second contact having a passage therethrough disposed coaxially with said first contact and adapted to be movable on the common axis of said contacts to contact said first contact, a casing enclosing said contacts and normally filled with a compressed gas, means connecting the passages of the first and the second contacts with the outside atmosphere, means to prevent leakage from the compressed gas in said casing between the contacting surfaces of the first and second contacts into said passages when said surfaces are in contact, a flange member provided on said second contact, a driving coil fixedly disposed so as to be closely coupled, in an electromagnetic manner, with said flange member, a switching element, a capacitor means to charge said capacitor, said capacitor being connected to said driving coil through said switching element, so that energy stored in said capacitor is discharged into said driving coil by the operation of said switching element to cause a current to flow through said driving coil, whereby said second contact will be separated from said first contact by the resulting repulsive force between said current in said driving coil and an induced current in said flange member.

3. A gas blast circuit breaker with electromagnetic contact actuating means comprising a first contact of hollow construction, a nozzle-shaped second contact disposed coaxially with said first contact and adapted to be movable on the common axis to normally contact said first contact, a casing enclosing said contacts filled with a compressed gas, passage means to connect the interiors of the first and the second contacts with the outside atmosphere, means to prevent leakage of the compressed gas from said casing from between the contacting surfaces of the first and second contacts when they are in contact, flange member provided on said second contact, a driving coil fixedly disposed so as to be closely coupled, in an electromagnetic manner, with said flange member a switching element, a capacitor, means to change said capacitor from ground, said capacitor being connected to said driving coil through said switching element, and means to operate said switching element from the ground potential side through an electromagnetic wave, so that energy stored in said capacitor will be discharged into said driving coil by the operation of said switching element to cause a current to flow through said driving coil, whereby said second contact will be separated from said first contact by the resulting repulsive magnetic force between said current in said driving coil and an induced current in said flange member.

4. A gas blast circuit breaker with electromagnetic actuating means comprising a casing normally filled with a compressed gas, a stationary contact and a nozzleshaped movable contact provided in said casing, a flange member on said nozzle-shaped movable contact adapted to be driven in the direction for separation of said movable contact from said stationary contact by an electromagnetic repulsive force caused by the discharge current of the capacitor, a driving coil fixedly disposed so as to be closely coupled in electromagnetic manner with said flange member, a disconnecting switch connected in series with the above mentioned parts, said disconnecting switch being operated by compressed gas, a capacitor, a device to discharge said capacitor substantially simultaneously with the application of a trip signal for operation of the circuit breaker, said disconnecting switch being provided with means to provide a predetermined time lag to open said disconnecting switch after the circuit breaker operation of said main breaker caused by the discharge current of said capacitor.

5. A gas blast circuit breaker with electromagnetic con tact actuating means comprising a first contact of hollow construction, a nozzle-shaped second contact disposed coaxially with said first contact and adapted to be movable on the common axis to contact said first contact, a casing enclosing said contacts and normally filled with a compressed gas, a passage to connect the interiors of the first and the second contacts with the outside atmosphere, means to prevent leakage of the compressed gas from said casing from between the contacting surfaces of the first and second contacts when they are in contact, a flange member provided on said second contact, a driving coil fixedly disposed so as to be electromagnetically closely coupled with said flange member, a switching element, a plurality of capacitors, means to change said capacitors, said capacitors being connectable to said driving coil through said switching element, said switching element including change-over switch means adapted to connect said capacitors selectively and successively, with said driving coil to effect the opening of said second contact, said members being combined so that an energy stored in said capacitors is discharged into said driving coil by the operation of said switching element to cause a current to flow through said driving coil, whereby said second contact will be separated from said first contact by the resulting repulsive force between said current in said driving coil and an induced current in said flange member.

References Cited by the Examiner UNITED STATES PATENTS 2,951,188 8/1960 Diebold 200-87 X 2,971,130 2/1961 Diebold 200-87 X FOREIGN PATENTS 1,323,018 2/1963 France,

ROBERT K. SCHAEFER, Primary Examiner.

ROBERT S. MACON, Examiner.

P. E. CRAWFORD, Assistant Examiner. 

1. A GAS BLAST CIRCUIT BREAKER WITH ELECTROMAGNETIC CONTACT ACTUATING MEANS COMPRISING A FIRST CONTACT, A SECOND CONTACT OF CONSTRUCTION NORMALLY IN CONTACT WITH SAID FIRST CONTACT AND HAVING A COAXIAL PASSAGE THERETHROUGH DISPOSED COAXIALLY WITH SAID FIRST CONTACT AND ADAPTED TO BE MOVABLE ON THE COMMON AXIS TO CONTACT SAID FIRST CONTACT, A CASING WHICH ENCLOSES BOTH SAID CONTACTS AND IS NORMALLY FILLED WITH A COMPRESSED GAS AND ELECTRICALLY INSULATED FROM GROUND POTENTIAL, MEANS TO PREVENT LEAKAGE OF THE COMPRESSED GAS IN SAID CASING BETWEEN THE CONTACTING SURFACES OF THE FIRST AND SECOND CONTACTS WHEN IN CONTACT, A FLANGE MEMBER PROVIDED ON SAID SECOND CONTACT, A DRIVING COIL WHICH IS FIXEDLY DISPOSED SO AS TO BE CLOSELY COUPLED, IN AN ELECTROMAGNETIC MANNER, WITH SAID FLANGE MEMBER, A SWITCHING ELEMENT, A CAPACITOR CONNECTABLE TO SAID DRIVING COIL THROUGH SAID SWITCHING ELEMENT, AND MEANS TO CHARGE SAID CAPACITOR, SAID SWITCHING ELEMENT, CAPACITOR AND DRIVING COIL BEING COMBINED SO THAT AN ELECTROSTATIC CHARGE IN SAID CAPACITOR IS DISCHARGE INTO SAID DRIVING COIL UPON OPERATION OF SAID SWITCHING ELEMENT TO CAUSE A CURRENT TO FLOW THROUGH SAID DRIVING COIL, WHEREBY SAID SECOND CONTACT WILL BE SEPARATED FROM SAID FIRST CONTACT BY THE RESULTING REPULSIVE FORCE BETWEEN SAID CURRENT IN SAID DRIVING COIL AND AN INDUCED CURRENT IN SAID FLANGE MEMBER. 